Use Of A Preparation Liquid Of Low Viscosity And Low Water Content For The Treatment Of Threads

ABSTRACT

The present invention refers to a method for the treatment of threads, wherein after spinning, a preparation liquid having a viscosity of 15 to 70 mm 2 /s at 25° C. and a water content of 0 to 6% by weight is applied to the threads.

The present invention refers to the use of a preparation liquid with low viscosity and low water content for the treatment of threads.

It is known that synthetic melt-spun threads are treated with an emulsion of a preparation liquid after extrusion in order to enable further processing, i.e. drawing, winding and textile processing. The so-called “drawing” of the extruded threads between heated rolls of different speeds is necessary in order to obtain the required strength and elongation as well as textile properties through parallel orientation of the polymer molecules. It is known that extremely high pressures in the melt and high extrusion speeds provide orientation, which, however, is not comparable with the orientation of the macromolecules during the described “drawing”.

The treatment of the threads with preparation liquids as emulsions is an important part of the entire production and above all further processing process, since this is jointly responsible for optimum conditions in all production and processing stages of the yarns.

The production of such emulsions is complex because water of high purity is required and this water is evaporated again during the production process.

In order to avoid the associated consumption of energy and resources, attempts have been made to apply the pure preparation liquids required for production and processing to the yarns without producing an emulsion. One reason for the failure of these experiments was the high viscosity of the preparation liquids. In order to reduce this viscosity, the preparation liquids were mixed with diluents, generally low-viscosity mineral oils. However, these highly volatile oils caused complications throughout the technical process of thread production (see introduction to EP 2 712 956 A1).

EP 2 712 956 A1 also discloses a treatment agent for synthetic fibres, aqueous liquids thereof and processing methods for synthetic fibres and synthetic fibres. The treatment agent contains water in a concentration of 10 to 60% by weight.

WO 2011/009498 A1 describes a method for melt spinning, drawing and winding a multi-filament thread and a device for carrying out the method. The method comprises using a preparation liquid having a water content of less than 8% by weight and a viscosity of 90 to 100 mm²/s for application to the thread. The disadvantage of this method is that preparation liquids with such viscosity wet the polymer surfaces poorly and must therefore be heated before application, which is technically complex and nevertheless leads to irregular oil wetting.

It is also known from WO 2009/141424 that threads spun from the melt are drawn without the application of a preparation liquid and that the treatment liquids required for the processing of the threads are only applied as oil-water emulsions after drawing.

DE 10 2013 219 584 A1 describes a method and a device for the production of fully drawn threads in which a treatment liquid with a kinematic viscosity of 100 to 200 mm²/s is applied to the threads at 30° C. as an aqueous emulsion. The water content in the treatment liquid is 40 to 60% by weight.

A process for producing polyethylene terephthalate threads using a preparation containing not more than 10% by weight of water as a lubricant for the threads is described in DE 2118 316 A1.

The WO 2012/013367 A1 discloses a device for melt spinning, drawing and winding of a multi-filament thread with a spinning device, a drawing device, a winding device and a preparation device, which is formed by two separate preparation stations for wetting the thread. The wetting liquid is an oil-water emulsion or a low-viscosity pure oil.

The preparation liquids described above, which are used as oil-water emulsions, require a considerable amount of effort to produce the emulsions. In addition to the provision of water of suitable quality, the use of preservatives is necessary to protect the emulsions from microbial attack during storage and application. The spinning of the threads typically involves a thermal treatment of the threads. Consequently, when using preparation fluids as oil-water emulsions, it is necessary to evaporate the water contained to achieve the temperatures required for thermal treatment of the threads. This requires a considerable additional expenditure of energy on the heated godets.

The use of low-viscosity pure oils as preparation fluids leads to migration of the preparation fluid into the polymer interior, which considerably restricts further processing of the threads after a short storage period.

The object of this invention is to provide a low-water preparation liquid with a low viscosity and excellent wetting properties, as a replacement for the oil-water emulsions described above, for the treatment of threads, which guarantees a high storage stability of the threads.

The object is solved by a method for the treatment of threads, wherein after spinning a preparation liquid with a viscosity of 15 to 70 mm²/s at 25° C. and a water content of 0 to 6% by weight is applied to the threads.

In a preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid has a viscosity of 20 to 50 mm²/s at 25° C.

In a more preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid has a viscosity of 30 to 45 mm²/s at 25° C.

The viscosity is determined according to ASTM D7042.

In a preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid has a water content of 0.5 to 4% by weight.

In a more preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid has a water content of 0.8 to 3% by weight.

In another preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid does not contain any organic solvent.

In a preferred embodiment in conjunction with any of the above or below described embodiments, the preparation fluid is applied to the threads prior to drawing.

In another preferred embodiment in conjunction with any of the above or below embodiments, the preparation fluid is applied to the threads after drawing.

In another preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid is applied to the threads in partial amounts before and after drawing.

Furthermore, the present invention refers to the use of a preparation liquid with a viscosity of 15 to 70 mm²/s at 25° C. and a water content of 0 to 6% by weight for the treatment of threads.

All preferred embodiments refer both to the method in accordance with the invention and to the use of the preparation liquid in accordance with the invention.

FIG. 1 shows a bobbin structure using the method according to the invention according to example 3.

FIG. 2 shows a bobbin structure using a method not in accordance with the invention, in which a preparation liquid was applied as an emulsion and otherwise proceeded in analogy to example 3.

FIG. 3 shows a bobbin structure using a method not in accordance with the invention according to comparison example 2.

FIG. 4 shows a bobbin structure using the method according to the invention according to example 4.

The bobbin structure using the method according to the invention shown in FIGS. 1 and 4 is significantly more uniform than the bobbin structure shown in FIGS. 2 and 3, which shows “slipped” yarn layers which, when the bobbin is unwound, e.g. for weaving, can cause irregularities due to tension fluctuations.

In the method or use according to the invention, the threads are formed from extruded filament bundles consisting of synthetic melt-spun filaments. In a preferred embodiment in conjunction with any of the embodiments described above or below, the filaments are formed from a polymer selected from the group consisting of polyesters, polyamides, polyolefins and mixtures thereof. The polymer is particularly preferably selected from the group consisting of polyethylene terephthalate, polyamide 6, polyamide 6.6, polypropylene and mixtures thereof, in particular polyethylene terephthalate. The blends of polymers are in particular bicomponent fibres.

In a preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid is composed of components selected from the groups of lubricants, emulsifiers and additives. Especially preferred is the preparation liquid composed of components selected from each of the groups of lubricants, emulsifiers and additives.

In a preferred embodiment in conjunction with any of the above or below described embodiments, the preparation fluid contains at least one lubricant selected from Group I-V base oils (see item E.1.3 of Annex E of March 2015 to Engine Oil Licensing and Certification System API 1509, Seventeenth Edition, September 2012), more preferably selected from Group III (mineral oils) and Group V (other oils). Group V lubricant is especially selected from ester oils and polyalkylene glycols (PAG).

In a preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid contains at least one emulsifier selected from the group consisting of fatty alcohol alkoxylates, fatty acid alkoxylates, ester alkoxylates, caster oil alkoxylates, in particular caster oil ethoxylates, polyethylene glycol esters, ethoxylated and non-ethoxylated partial glycerides, more preferably selected from fatty alcohol alkoxylates and ester alkoxylates.

In a preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid contains at least one additive selected from the group consisting of phosphorus-containing additives, sulfur-containing additives and nitrogen-containing additives.

The phosphorus-containing additive is especially selected from phosphoric acid esters and phosphoric acid partial esters. The sulphur-containing additive is especially selected from sulphates and sulphonates. The nitrogen-containing additive is especially selected from amines and amides.

In another preferred embodiment in conjunction with any of the above or below described embodiments, the additive is present as an alkali or alkaline earth salt or the additive is neutralized with a nitrogen-containing base.

In a further preferred embodiment in conjunction with any of the above or below described embodiments, the preparation liquid contains at least one further component selected from the group consisting of defoamers, antioxidants, preservatives and corrosion inhibitors.

The use of preparation liquids with a viscosity of 15 to 70 mm²/s at 25° C. is advantageous, since the application of very low viscosity preparation liquids (below 15 mm²/s at 25° C.) has' the disadvantage that these preparation liquids migrate into the polymer or are absorbed by the polymer after a short time, which results in a lack of storage stability and leads to serious processing problems. The use of preparation liquids with a viscosity of over 70 mm²/s at 25° C. leads to irregular oil wetting and may require heating of the preparation oil prior to application, as described in WO 2011/009498 A1.

The water content of the preparation liquid is in the range of 0 to 6% by weight, since a water content of more than 6% by weight requires a high energy input for the evaporation of the water.

The preparation of the threads and the application of the preparation liquid can be carried out in a manner known per se, e.g. as described in DE 10 2013 219 584 A1 or WO 2009/141424.

Due to the low viscosity of the preparation liquid used according to the invention, heating of the preparation liquid before application is not necessary. The preparation liquid is neither diluted with water nor with an organic solvent.

In the process, the threads can be drawn with or without heat input over godets running at different speeds, whereby the preparation liquid is applied when the individual filaments are combined to form a filament bundle and the drawing and holding forces required for drawing are achieved by multiple wraps. Furthermore, the preparation liquid can be applied before drawing with partial wrapping, as described in DE 10 2013 219 584 A1.

Alternatively, drawing can be carried out without prior application of the preparation by simple partial wrapping of the godets and the preparation liquid can be applied after drawing. It is also possible to apply the preparation liquid in partial quantities before and after drawing with partial and multiple wrapping, e.g. as described in WO 2012/013367 A1.

After drawing, the threads are often guided through so-called interlacing jets in which compressed air is applied to the threads. A further advantage of the method according to the invention or the use according to the invention is that there is no significant spray-off of the preparation liquid from the threads.

Furthermore, this invention can prevent electrostatic charging during further processing of the threads and guarantee a good storage stability of the threads, which is preferably at least 6 months. Since the production of the threads and their further processing are usually separated in time and space, the storage stability of the produced threads is an important aspect.

Surprisingly and unexpectedly, tests on suitable machines have shown that the use of low-water preparation liquids in a method according to the invention produces the best yarn qualities (high uniformity of dyeing, better bobbin structure) in comparison with yarns which have been subjected to an oil-water emulsion. The better bobbin structure can be seen from a comparison of the bobbins in FIGS. 1 and 4, where the threads were treated according to the method according to the invention, and the bobbins in FIGS. 2 and 3, which were not treated according to the method according to the invention.

These tests show further advantages of the method according to the invention, namely the excellent wetting properties of the preparation liquid with low viscosity, low evaporation on hot surfaces, such as heated applicators, and the avoidance of highly flammable diluents or other accessories.

In the following, the invention is explained using examples.

EXAMPLE 1

A thread of 24 individual filaments of polyethylene terephthalate (PET) was spun and drawn over heated rolls with partial wrapping according to the method described in WO 2009/141424. After drawing, the thread had a fineness of 60 dtex.

A preparation liquid with a water content of 1.25% by weight and a viscosity of 18.10 mm²/s at 25° C. was applied after drawing.

Composition of the Preparation Liquid:

lubricant (Group V, ester oil) 72.5% by weight lubricant (Group III) 10% by weight ester alkoxylate 2% by weight fatty alcohol alkoxylate 5% by weight corrosion protection 5% by weight Additive (total) 5.5% by weight

The mechanical yarn data was in the usual range. Measurements also showed that when the yarns are stored for 6 months, the applied preparation quantity does not change, i.e. no absorption of the preparation liquid by the polymer takes place.

COMPARISON EXAMPLE 1

The spinning and drawing of the thread from PET took place as in example 1, but from 36 individual filaments and with a resulting fineness of 83 dtex.

A preparation liquid with a water content of 0.28% by weight and a viscosity of 12.50 mm²/s at 25° C. was applied after drawing.

Composition of the Preparation Liquid:

lubricant (Group V, ester oil) 66.5% by weight lubricant (Group III) 25% by weight ester alkoxylate 5% by weight fatty alcohol alkoxylate 2% by weight corrosion protection 0.5% by weight Additive (total) 1% by weight

The mechanical yarn data were in the usual range, but a stripy dyeing was found.

Further investigations on the stability of the preparation application were carried out. For this purpose, a preparation application of 0.91% by weight was determined immediately after manufacture, which however dropped to 0.78% by weight after a storage period of the bobbins of 30 days and to 0.65% by weight after a further 30 days. The preparation application was determined by extraction of a yarn sample with a suitable solvent and gravimetric evaluation of the extractable preparation liquid.

The decrease of the preparation application within a comparatively short storage time is caused by an absorption of the preparation liquid by the polymer and leads to big problems during the further processing of the bobbins or can make further processing impossible.

EXAMPLE 2

The spinning and drawing of the thread from PET took place as in example 1, but from 36 individual filaments and with a resulting fineness of 138 dtex.

A preparation liquid with a water content of 1.85% by weight and a viscosity of 34.8 mm²/s at 25° C. was applied after drawing.

Composition of the Preparation Liquid:

lubricant (Group V, ester oil) 55% by weight lubricant (Group V, PAG) 5% by weight lubricant (Group III) 20% by weight ester alkoxylate 5% by weight fatty alcohol alkoxylat 7% by weight additive (total) 8% by weight

The running behaviour of the yarns was inconspicuous and only a small spray off was observed during the interlacing of the yarns. Furthermore, the dyeing uniformity of the yarns was good. The yarns can be used as weft yarn without any problems.

After a storage period of 60 days, no reduction of the preparation application could be observed.

COMPARISON EXAMPLE 2

A thread was spun from 48 individual filaments of PET.

An emulsion of a preparation liquid was applied before drawing which was DAKOLUB L 2505 HY. The drawing was achieved by multiple wrapping of the yarn. The fineness after drawing was 209 dtex.

The dyeing was uniform. The bobbin structure is shown in FIG. 3. It clearly shows “slipped” yarn layers, which can cause irregularities due to tension fluctuations when unwinding the bobbin, e.g. for weaving.

EXAMPLE 3

A thread was spun from 24 individual filaments of PET.

A preparation liquid with a water content of 2.7% by weight and a viscosity of 36.5 mm²/s at 25° C. was applied before drawing. Drawing was achieved by multiple wrapping of the yarn as in comparison example 2. The fineness after drawing was 73 dtex.

Composition of the Preparation Liquid:

lubricant (Group V, ester oil) 75% by weight lubricant (Group V, PAG) 5% by weight ester alkoxylate 5% by weight fatty alcohol alkoxylate 4% by weight additive (total) 11% by weight

The dyeing was uniform and comparable with a standard yarn, in which a preparation liquid was applied as an emulsion.

Due to the low water content, 12% energy could be saved compared to a standard thread in which the preparation liquid was applied as an emulsion. The energy saving was determined by the power consumption of the heated godets.

The bobbin structure is shown in FIG. 1. It is more uniform than the bobbin structure of a standard yarn in which a preparation liquid was applied as an emulsion, as shown in a comparison of FIGS. 1 and 2.

Furthermore, no capillary breaks occurred during further processing.

EXAMPLE 4

A thread was spun from 48 individual threads of PET.

A preparation liquid with a water content of 2.5% by weight and a viscosity of 39 mm²/s at 25° C. was applied before drawing. Drawing was achieved by multiple wrapping of the yarn as in comparison example 2. The fineness after drawing was 209 dtex.

Composition of the Preparation Liquid:

lubricant (Group V, ester oil) 75% by weight lubricant (Group V, PAG) 5% by weight ester alkoxylate 5% by weight fatty alcohol alkoxylate 4% by weight additive 11% by weight

Due to the low water content, 28% energy could be saved in comparison to a standard yarn according to comparison example 2. The energy saving was determined by the power consumption of the heated godets.

The bobbin structure is shown in FIG. 4. It is more uniform than the bobbin structure in FIG. 3, which was carried out using a method not in accordance with the invention according to comparison example 2 and clearly shows “slipped” yarn layers. 

1. Method for the treatment of threads, wherein after spinning a preparation liquid having a viscosity of 15 to 70 mm²/s at 25° C. and a water content of 0 to 6% by weight is applied to the threads.
 2. Method according to claim 1, wherein the preparation liquid has a viscosity of 20 to 50 mm²/s at 25° C.
 3. Method according to claim 2, wherein the preparation liquid has a viscosity of 30 to 45 mm²/s at 25° C.
 4. Method according to claim 1, wherein the preparation liquid has a water content of 0.5 to 4% by weight.
 5. Method according to claim 4, wherein the preparation liquid has a water content of 0.8 to 3% by weight.
 6. Method according to claim 1, in which the preparation liquid is applied before drawing the threads.
 7. Method according to claim 1, where the preparation liquid is applied after drawing the threads.
 8. Use of a preparation liquid having a viscosity of 15 to 70 mm²/s at 25° C. and a water content of 0 to 6% by weight for the treatment of threads. 